Which are MLC / TLC MicroSD cards?

I like to buy the MLC MicroSD card that uses MLC technic, that will lessen the chance / time that data corrupts.

Both types corrupt after certain cycles of erase/programming, but MLC will last longer.

So my question is: Which Sandisk MicroSd cards are based on MLC?

(why is this information not published as public data? Professionals or serious users  like to know )

Thanks!

:smiley:   Hi Chihwahli,

Dear member of SanDisk Community, welcome.

_For more certainty, also you can send the question to the Support Team: _ Link: http://kb.sandisk.com/app/ask/

Friend:

Single-level cell ( SLC ) and multi-level cell ( MLC ) Flash memory are similar in their design.

MLC Flash devices cost less and allow for higher storage density.
SLC Flash devices provide faster write performance and greater reliability, even at temperatures above the operating range of MLC Flash devices.

These factors make SLC Flash a good fit in embedded systems, while MLC flash makes it possible to create affordable mobile devices with large amounts of data storage.

In order to select the right Flash memory for an application, it is important to analyze the how it will be used.

For example, product developers integrating memory into a portable barcode reader will most likely need SLC Flash since performance and durability are important.
On the other hand, a company building a portable media player will need the low cost and high density of MLC to price their device competitively.

_ SLC Flash is used in commercial and industrial applications that require high performance and long-term reliability._
Some applications include industrial grade Compact Flash cards or Solid State Drives (SSDs).

_ MLC Flash is used in consumer applications that do not require long term reliability such as consumer grade USB Flash drives, portable media players, and Compact Flash cards._

The read speeds between SLC and MLC are comparable. Reading the level of the Flash cell compares the threshold voltage using a voltage comparator. Thus, the architecture change does not affect sensing.
In general, the read speeds of Flash are determined by which controller is used.

The endurance of SLC Flash is 10x more than MLC Flash.
The endurance of MLC Flash decreases due to enhanced degradation of the substrate.
This is a main reason why SLC Flash is considered industrial grade Flash and MLC Flash is considered consumer grade Flash.

Higher temperatures cause more leakage in the cells. Combined with the increased sensitivity required to differentiate between the levels, this leakage will cause the sensors to read the wrong level.
As a result, the operating temperature of MLC spans only the commercial range.
Leakage is not significant in SLC Flash and thus, it can operate in an industrial temperature range.

Then, it is important to evaluate what type of Flash memory your system needs.

If performance and durability are essential for your system, SLC Flash incorporated.
If low cost and high density are essential, MLC Flash is the right choice.

The high-performance MLC technology with three bits per cell, is commonly referred to as Triple Level Cell ( TLC ), which uses eight states.

_ Enjoy!! _

Regards, Alfred.

Thanks for this initial answer.

I have frequent erase and proram cycles with my micro SD card. That’s why I want to know which card uses 2 bits per cell.

The SLC cards are just too expensive, those are out of my reach.

Will ask the support team and put the answer here if I get it.

:smiley:   Hi Chihwahli,

[ That’s why I want to know which card uses 2 bits per cell. ]

Well,

The multi-level cell ( MLC ) is a memory element capable of _ storing more than a single bit of information. _

MLC NAND flash is a flash memory technology using multiple levels per cell to allow more bits to be stored using the same number of transistors.

MLC NAND flash memory has four possible states per cell, so it can store two bits of information per cell.

MLC Flash is used in consumer applications that do not require long term reliability such as consumer grade _ USB Flash drives , portable media players, and Compact Flash cards. _

Luck.

Regards, Alfred.

Hi Cacho

I also have a clarification regarding the Cell type for the microSDHC we are presently using in our product.

The card  currently used is SDSDQM-008G-B35 (8GB microSDHC card). We would like to know if this is SLC/MLC/TLC type?

The intended use of this card is to save both program and user data for our product which we are designing. Since this serves as storage space for all codes-  including system and application code, high reliabilty is preferred since any failure on the card can render the product unusable. 

Does the above card fall under the more reliable SLC category?

Thanks!

Regards,

KSP

:smiley:   Hi KSP,

Dear member of SanDisk Community, welcome.

1-  [  SDSDQM-008G-B35 (8GB microSDHC card). We would like to know if this is SLC/MLC/TLC type?  ]

Is MLC.

2-  [  Does the above card fall under the more reliable SLC category?  ]

2.1-    _ SLC Flash is used in commercial and industrial applications that require high performance and long-term reliability._
Some applications include industrial grade Compact Flash cards or Solid State Drives (SSDs).

2.2 -   Traditionally, each cell has two possible states, so one bit of data was stored in each cell in so-called single-level cells, or SLC flash memory.

SLC memory has the advantage of faster write speeds, lower power consumption and higher cell endurance.

However, because SLC memory stores less data per cell than MLC memory, it costs more per megabyte of storage to manufacture.

Due to faster transfer speeds and longer life, SLC flash technology is used in high-performance memory cards.

2.3-    It is important to understand what makes up a Flash cell, before explaining the variation between SLC and MLC Flash.

Each cell consists of a single transistor, with an additional “floating” gate that can store electrons.

A large voltage difference between the drain and the source, Vd – Vs, creates a large electric field between the drain and the source.

The electric field converts the previously nonconductive poly-Si material to a conductive channel, which allows electrons to flow between the source to the drain.

The electric field caused by a large gate voltage, Vg, is used to bump electrons up from the channel onto the floating gate.
As an electron travels closer to the drain, it gains more momentum and thus, more energy.

But, this amount of energy is not enough to push an electron onto the floating gate.

Electrons with high momentum near the drain can sometimes bump into Si (Silicon) atoms .

This bump gives the electron enough energy to be pushed onto the floating gate.

The number of electrons on the floating gate affects the threshold voltage of the cell Vt.

This effect is measured to determine the state of the cell.

2.4-    SLC Flash stores _ one bit value per cell _, which basically is a voltage level. The bit value is interpreted as a “0” or a “1”.

Since there are only two states, it represents only one bit value, each bit can have a value of “programmed” or “erased.”

For more data, you can send the question to the Support Team : Link: http://kb.sandisk.com/app/ask/

Enjoy!!

Regards, Alfred.                                                                                       (Google translated)

Hi Alfred

Thanks for the very detailed description and also insights on the cell structure. Very informative and detailed.

Does it mean that SLC technology is not used for microSDHC card types since it is not cost efficient? 

Regards,

KSP

:smiley:   Hi KSP,

However, SLC technology is used for microSDHC card types.

It depends on the manufacturer, if you consult different brands, see what some utlizan this topic, as a marketing tool.

Other companies, do not say anything about this, because they are trade secrets.

I_n case of SanDisk, please, consult_ to the _ Support Team _, link: http://kb.sandisk.com/app/ask/

Luck, and then you tell us, what happened, please.

Regards, Alfred.                                                            (Google translated)

Hi Alfred,

Thanks, again.

I have posted the query with the support team. Shall updateh ere once i get response from them :smiley: :smiley:

Regards,

KSP

Hi Alfred

I am afraid I do not have anything else to add to this conversation. The customer service  replied back saying they do not disclose such details regarding cell structures :cry:

So probably we do not have much choice but to continue using this card.

Regards,

KSP

:smiley:   Hi KSP,

I’m sorry, but do not worry, because SDSDQM-008G-B35 ( SanDisk 8GB microSDHC card), is excellent.
Link: http://www.sandisk.com/products/memory-cards/microsd/class4/?capacity=8GB

With respect to the cell structure, thought so, because SanDisk does not specify the topic (in card) on the official website.

But if, in SSD , links: http://www.sandisk.com/assets/docs/wp001_flash_management_final_final.pdf
                                    http://www.sandisk.com/assets/docs/wp003_guardian_technology_platform_final.pdf
                                    http://www.sandisk.com/goto/x300s/pdf/x300_datasheet.pdf

The company Kingston, does not specify the topic (in card), on their official website.

The company Panasonic, has an industrial line (in SD card, made in Japan).
Link: http://panasonic.net/avc/sdcard/industrial_sd/lineup.html

Luck.

Regards, Alfred.                                                                     (Google translated)

Does anyone have an update to this? I’ve been trying to find out if the Extreme, Extreme Pro, and/or Extreme Plus microSD cards use TLC or MLC.

If what this thread is saying is that Sandisk does NOT disclose whether they are using MLC or TLC, that’s really frustrating to me as a consumer.

For cheaper SD cards, not disclosing this detail is fine, but for high-dollar cards this is an important question IMO. MLC tends to last longer and write faster than TLC. Beyond benchmarks, MLC NAND tends to give better real-world performance, especially in regards to writing. As this is an investment, I want the better durability and faster speeds of MLC, and I am willing to pay for it.

Greetings everyone.

I bought a SanDisk Ultra 32GB MicroSD HC1 for my dashcam, a Transcend DP200. I lost the bundled microsd which according to the literature which came with the card was a Transcend Ultimate 600x  and which according to the Transcend website is MLC.

Since getting the replacement I sometimes get problems with the dashcam including  (sometimes)  it not recording which defeats the purpose of having it. I wont be able to recover the bundled card that came with it since I am pretty sure  it got stolen by one of my co-employees  while I  left it on my desk when I was syncing the camera to my computer (long story).

Hope you guys can shed insight on whether you think my problem is compatibility of the Transcend dashcam and the replacement SanDisk card in which case I have to hunt for a replacement Transcend card or if  it is defect in the dashcam itself.

TIA  

I just got off the phone with customer service, I was told that All sd and micro sd cards are MLC

Recently you requested personal assistance from our on-line support center. Below is a summary of your request and our response.

Thank you for allowing us to be of service to you.

Subject
pre purcahse

Discussion Thread
Response Via Email (Sasha G.) 05/10/2018 09:04 AM
Dear Bob,

Thank you for contacting SanDisk® Global Customer Care. As per our recent conversation, I understand that you would like to purchase High Endurance microSD cards for your Dashcam.

Please allow us to inform you that all memory cards manufactured by SanDisk are Multi Level Cell (MLC) and allows higher storage density. Moreover, SanDisk High Endurance microSD cards are recommended for Dashcam due to their capacity of constant read and write operations. These cards has a read and write speed of upto 20 MB/s and are C10 microSD cards.

You may refer to the below link in order to know more on the memory card:

  • SanDisk® High Endurance microSD cards for Dashcam

Also, you can purchase the card from our Online Store and avail a special discount of 10% by using the promo code: L642Z as a valuable customer.

Please reply to this email or call us with Incident Id: 4581014, should you require further assistance. We are glad to help!

Best regards,
Sasha G.
SanDisk® Global Customer Care

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